Cost-effectiveness and budget impact of immediate antiretroviral therapy initiation for treatment of HIV infection in Côte d'Ivoire: A model-based analysis

Abstract

Introduction: The Temprano and START trials provided evidence to support early ART initiation recommendations. We projected long-term clinical and economic outcomes of immediate ART initiation in Côte d'Ivoire.

Methods: We used a mathematical model to compare three potential ART initiation criteria: 1) CD4 <350/μL (ART<350/μL); 2) CD4 <500/μL (ART<500/μL); and 3) ART at presentation (Immediate ART). Outcomes from the model included life expectancy, 10-year medical resource use, incremental cost-effectiveness ratios (ICERs) in $/year of life saved (YLS), and 5-year budget impact. We simulated people with HIV (PWH) in care (mean CD4: 259/μL, SD 198/μL) and transmitted cases. Key input parameters to the analysis included first-line ART efficacy (80% suppression at 6 months) and ART cost ($90/person-year). We assessed cost-effectiveness relative to Côte d'Ivoire's 2017 per capita annual gross domestic product ($1,600).

Results: Immediate ART increased life expectancy by 0.34 years compared to ART<350/μL and 0.17 years compared to ART<500/μL. Immediate ART resulted in 4,500 fewer 10-year transmissions per 170,000 PWH compared to ART<350/μL. In cost-effectiveness analysis, Immediate ART had a 10-year ICER of $680/YLS compared to ART<350/μL, ranging from cost-saving to an ICER of $1,440/YLS as transmission rates varied. ART<500/μL was "dominated" (an inefficient use of resources), compared with Immediate ART. Immediate ART increased the 5-year HIV care budget from $801.9M to $812.6M compared to ART<350/μL.

Conclusions: In Côte d'Ivoire, immediate compared to later ART initiation will increase life expectancy, decrease HIV transmission, and be cost-effective over the long-term, with modest budget impact. Immediate ART initiation is an appropriate, high-value standard of care in Côte d'Ivoire and similar settings.

Fig 1. One-way sensitivity analysis, Immediate ART strategy compared to ART<350/μL.

This tornado diagram depicts the impact of uncertainty in various input parameter ranges on the incremental cost-effectiveness ratio (ICER) of Immediate ART compared to ART<350/μL, except for asterisked bounds (*), which are compared to ART<500/μL. The bold black vertical line crosses the horizontal axis at the base-case ICER of $680/YLS. Each bar represents the effect of changing one input parameter across its plausible range, and plotting the resulting ICERs of Immediate ART compared to ART<350/μL (or to ART<500/ μL in cases where Immediate ART does not display extended dominance compared to ART<500/ μL; see Methods for details). Along the vertical axis, the parameter varied is reported as (Base-case value; value leading to lower ICER-value leading to higher ICER). No changes in individual parameters increase the ICER to over the 2017 annual per capita GDP in Côte d’Ivoire of $1,600 (dashed vertical line). ART: antiretroviral therapy; YLS: years of life saved; GDP: annual per capita gross domestic product. OD: opportunistic disease.

Fig 2. Multi-way sensitivity analysis on transmission rate, CD4 count at diagnosis, and ART costs in a model-based analysis of Immediate ART initiation in Côte d’Ivoire.

This shows the impact of uncertainty in three key input parameters on the incremental cost-effectiveness ratio (ICER) of Immediate ART compared to ART<350/μL. We varied transmission rates across reported 95% confidence intervals on the vertical axis. On the horizontal axis, we varied the CD4 count at which transmitted cases present to care. Panel A represents a yearly first-line ART cost of $75. Panel B represents base-case ART costs. The base-case combination of input parameters is marked with the X. The parameter combination at which Immediate ART becomes cost-saving is marked with an O. Panel C represents yearly first-line ART costs that are 1·5x base-case values ($135). Combinations of the above parameters that resulted in ICERs that are cost-saving are in green, <0·5x the Côte d’Ivoire annual per capita GDP ($1,600) in yellow, 0·5-1x GDP in orange, and >1x GDP in red. ART: antiretroviral therapy; GDP: annual per capita gross domestic product.

Fig 3. HIV care budget increase and reduction in transmissions by ART initiation strategy and CD4 count at presentation to care, both after 10 years.

The 10-year change in budget, top, and 10-year change in transmission, bottom, for the ART<500/μL (blue) and Immediate ART (orange) strategies compared to ART<350/μL, is shown by CD4 count at presentation to care ranging from 207/μL to 569/μL (base-case 259/μL). ART<500/μL and Immediate ART proportionally reduce transmissions substantially more than they increase the budget at 10 years. If incident cases present with higher CD4 counts, due to increased testing and outreach, the reduction in transmission is even greater. ART: antiretroviral therapy.